Centaurea cyanus. Centaurea are also known as Bachelor's Buttons. These familiar, charming, brightly-coloured pompoms on fuzzy grey stems, are well loved by humans and attractive to beneficial hover-flies. Blue Boy is at home in borders, with herbs, or in the kitchen garden. Direct sow Blue Boy cornflower seeds at repeated intervals in April to June to extend bloom. Centaurea can also be planted in October on the Coast. Blue Boy has the traditional vivid blue blossoms, tall growing for masses of cut flowers. Centaurea flowers also dry particularly well. Tear fresh flower petals for use in salads, teas, or fancy drinks. Plant height 90cm (36"). It is drought tolerant once established, so good for xeriscaping.
An annual plant that also answers to Cornflower, Bachelor’s Button, Bluebottle, Hurtsickle, Hardheads, Knapweed, and Star Thistle. We use the genus name to keep it nice and simple. Grows well in any ordinary, well drained garden soil. Seeds will flourish within the pH range of 5.5-7.0. Deadhead regularly to prolong blooming. You will find planting several times over the spring will produce a longer bloom time throughout summer and early fall.
Season & Zone
Exposure: Full sun
Direct sow starting just before last frost, and again every two weeks until end of May. Can be direct sown in autumn as well. Starting indoors is not necessary, but can be accomplished by keeping seed trays in the dark at the optimal soil temperature of 15-21°C (60-70°F). Move under bright lights once germination occurs, and transplant out in late spring, around mid-May.
Just cover the small seeds. Thin or space to 15-30cm (6-12″) apart.